Biology subjects

KC, P.

Publications and source records attributed to KC, P..

4 recordsLinked to original sources

bioRxiv2025

REGULATION OF HDL DYSFUNCTIONALITY BY PHOSPHATIDYLETHANOLAMINE LINKS POLY-UNSATURATED FATTY ACIDS WITH ATHEROSCLEROTIC CARDIOVASCULAR DISEASES

AimsLow plasma high-density lipoprotein (HDL)-cholesterol levels are associated with increased risk of atherosclerotic cardiovascular disease (ASCVD), potentially reflecting impaired antiatherogenic HDL functions. These latter are strongly influenced by the HDL phospholipidome, which is frequently altered in ASCVD patients. Several studies reported that plasma levels of phosphatidylethanolamine (PE) species, particularly PE (36:5), were positively associated with ASCVD, but the underlying mechanisms remain unclear. Plasma PE (36:5) exists as eicosapentaenoic (EPA)-PE and arachidonic acid (ARA)-PE, with the latter predominating in ASCVD. This study investigated whether the association of PE (36:5) with ASCVD might result from an impairment of the antiatherogenic functions of HDL. Methods and ResultsTotal PE and PE (36:5) content of large HDL isolated from 86 women with metabolic syndrome was positively associated with carotid intima-media thickness in multivariate regression analysis adjusted for traditional risk factors. In TgCETP x Ldlr-/- mice fed a high-cholesterol diet, the atherosclerotic plaque size was greater when reconstituted HDL (rHDL) containing ARA-PE was injected retro-orbitally, compared with injection of control rHDL containing only phosphatidylcholine (PC). In vitro, PE rHDL showed reduced cholesterol efflux capacity and impaired anti-inflammatory activity in THP-1 macrophages, together with diminished anti-oxidative activity against LDL oxidation compared to control rHDL. Strikingly, ARA-PE rHDL profoundly weakened of the HDL functions, while EPA-PE counteracted the ARA-PE-induced dysfunction and potentiated the functionality of rHDL. ConclusionThis study reveals a causal link between PE species, particularly ARA-PE, and HDL dysfunction, contributing to atherosclerosis. EPA-PE can restore HDL function, supporting the therapeutic potential of EPA reducing ASCVD risk.

cell biology↗

bioRxiv2024

Neuron synchronization analyzed through spatial-temporal attention

Across diverse organisms, the temporal dynamics of spiking responses between neurons, the neural synchrony, is crucial for encoding different stimuli. Neural synchrony is especially important in the insect antennal (olfactory) lobe (AL). Previous studies on synchronization, however, rely on pair-wise synchronization metrics including the cross-correlogram and cos-similarity between kernelized spikes train. These pair-wise analyses overlook an important aspect of synchronization which is the interaction at the population neuron level. There are also limited modeling techniques that incorporate the synchronization between neurons in modeling population spike trains. Inspired by recent advancements in machine learning, we leverage a modern attention mechanism to learn a generative normalizing flow that captures neuron population synchronization. Our method not only reveals the spiking mechanism of neurons in the AL region but also produces semi-interpretable attention weights that characterize neuron interactions over time. These automatically learned attention weights allow us to elucidate the known principles of neuron synchronization and further shed light on the functional roles of different cell types (the local interneurons (LNs), and projection neurons (PNs)) in the dynamic neural network in the AL. By varying the balance of excitation and inhibition in this neural circuit, our method further uncovers the pattern between the strength of synchronization and the ratio of an odorant in the mixture. Author SummaryThe olfactory system can accurately compute the mixture of volatile compounds emitted from distant sources, enabling the foraging species to exhibit fast and effective decisions. However, altering ratios of one of the compounds in the mixture could be perceived as a different odor. Leveraging the current understanding of neural synchronization on sensory neural regions of insects, we construct a spatial-temporal attention normalizing flow, which partially replicates the AL regions functionality by learning the spiking mechanics of neurons. Beyond providing insights of the spiking mechanism of neurons in the AL region, our method also produces semi-interpretable attention weights that characterize neuron interaction over time. These automatically learned attention weights allow us to dissect out the principles of neuron synchronization and interaction mechanisms between projection neurons (PNs) and local neurons (LNs). Utilizing our accurate model of these AL functionality, we show evidence that the behavioral relevant compounds are closely clustered together while varying the intensities of one of the behavioral compounds in the mixture could attenuate the synchronization

neuroscience↗

bioRxiv2022

Breasi-CRISPR: an efficient genome editing method to interrogate protein localization and protein-protein interactions in the embryonic mouse cortex

In developing tissues, knowing the localization and interactors of proteins of interest is key to understanding their function. This can be challenging when the researched protein lacks reliable antibodies. Here, we combine Easi-CRISPR with in utero electroporation to tag endogenous proteins within embryonic mouse brains. This method is called Breasi-CRISPR (Brain Easi-CRISPR), and enables knock-in of both short and long epitope tag sequences in genes of interest with high efficiency. Using Breasi-CRISPR, we were able to visualize epitope tagged proteins known to have either high or low expression levels, such as ACTB, LMNB1, EMD, FMRP, NOTCH1, and RPL22. Detection was possible by immunohistochemistry as soon as one day after electroporation at embryonic day 13 (E13). Two and five days after electroporation, we observed efficient gene editing in up to 50% of electroporated cells. Moreover, tagged proteins could be detected by immunoblotting in lysates from individual cortices two days after electroporation. Next, we demonstrated that Breasi-CRISPR enables the tagging of proteins with fluorophores in an efficient manner, allowing the visualization of endogenous proteins via live-imaging in organotypic brain slices two days after electroporation. Finally, we used Breasi-CRISPR to perform co-IP mass-spectrometry analyses of tagged autism-related protein FMRP to discover its interactome in the embryonic cortex. Together, these data show Breasi-CRISPR is a powerful tool with diverse applications that will propel the understanding of protein function in neurodevelopment.

developmental biology↗

bioRxiv2019

HVEM blockade initiates tumor cell death by innate immunity and improves anti-tumor response by human T cells in NSG immuno-compromised mice

BackgroundTNFRSF14 (herpes virus entry mediator (HVEM) delivers a negative signal to T cells through the B and T Lymphocyte Attenuator (BTLA) molecule and has been associated with a worse prognosis in numerous malignancies. A formal demonstration that the HVEM/BTLA axis can be targeted for cancer immunotherapy is however still lacking. MethodsWe used immunodeficient NOD.SCID.gc-null mice reconstituted with human PBMC and grafted with human tumor cell lines subcutaneously. Tumor growth was compared using linear and non linear regression statistical modeling. The phenotype of tumor-infiltrating leukocytes was determined by flow cytometry. Statistical testing between groups was performed by a non-parametric t test. Quantification of mRNA in the tumor was performed using NanoString pre-designed panels. Bioinformatics analyses were performed using Metascape, Gene Set Enrichment Analysis and Ingenuity Pathways Analysis with embedded statistical testing. ResultsWe showed that a murine monoclonal antibody to human HVEM significantly impacted the growth of various HVEM-positive cancer cell lines in humanized NSG mice. Using CRISPR/cas9 mediated deletion of HVEM, we showed that HVEM expression by the tumor was necessary and sufficient to observe the therapeutic effect. Tumor cell killing by the mAb was dependent on innate immune cells still present in NSG mice, as indicated by in vivo and in vitro assays. Mechanistically, tumor control by human T cells by the mAb was dependent on CD8 T cells and was associated with an increase in the proliferation and number of tumor-infiltrating leukocytes. Accordingly, the expression of genes belonging to T cell activation pathways, such as JAK/STAT and NFKB were enriched in anti-HVEM-treated mice, whereas genes associated with immuno-suppressive pathways were decreased. Finally, we developed a simple in vivo assay to directly demonstrate that HVEM/BTLA is an immune checkpoint for T-cell mediated tumor control. ConclusionsOur results show that targeting HVEM is a promising strategy for cancer immunotherapy.

immunology↗